The present invention relates to a drainage system for collecting seepage water in and draining it from the interior cavities of a masonry block wall back to a location outside of the masonry block cavity.
Masonry blocks are notorious for allowing water on the exterior side of the wall to enter into its central cavities through the joints between the blocks or through the blocks themselves. Once water has entered into the block cavities, it tends to seep inside the building and cause moisture problems. Water within the blocks and on their surfaces can cause damage to interior and exterior wall finishes.
There have been several attempts to solve the problem of water seepage through masonry block walls. For example, some have tried using blocks in the bottom course that have openings to drain the water from inside the block cavities to a gravel bed, and subsequently into a drain tile. Such systems were disclosed in U.S. Pat. No. 4,333,281 of Scarfone and U.S. Pat. No. 4,612,742 of Bevilacqua.
Others have tried to solve seepage problems by placing blocks at the bottom course that have interconnecting lateral slots which allow the water to drain laterally into an adjacent block. The water then drains to the exterior of the block wall by either a drain pipe extending from one of the blocks, as shown in U.S. Pat. No. 3,562,982 of Parezo, or by openings in the bottom course blocks which direct water to a gravel bed and subsequently to a drain tile, as shown in U.S. Pat. No. 4,486,986 of Cosenza.
Others have tried to solve masonry block drainage problems by placing a thin vent structure beneath the bottom block course to draw the water toward a gravel bed, which then directs the water to a drain tile. Such a system is shown in U.S. Pat. No. 4,381,630 of Koester.
One drawback of the abovementioned drainage systems is that they do not prevent water within the block cavities from contacting and seeping through the walls of the interior block cavities as it drains down through such cavities. Water passing from upper courses to lower courses must run down the walls of the interior cavity, causing such walls to become saturated with water, which eventually seeps to the interior and exterior surfaces of the building. One way to avoid this problem, as disclosed in U.S. Pat. No. 2,147,035 of Henderson, was to insert across vertical voids in the blocks a tar paper having holes punched in the middle to direct seepage from the outer walls toward the center of the voids. The seepage water was then drained at the bottom course of masonry blocks, where the water could be directed through holes in block externally and also internally beneath a floor slab.
Another drawback of many of the aforementioned drainage systems, moreover, is that they drain water toward the inside of the building rather than directing it to the exterior of the building away from the internal parts of the building. Such systems promote saturation of the ground underneath the wall and building structure. They are difficult to install and hinder access to gravel beds and drain tiles under the structures.
Another problem with many, if not most, of the aforementioned drainage systems is that they do not collect water from the block cavities at a level other than the bottom course. Consequently, water that has entered a block wall at upper courses must run down the walls of the interior cavities to the bottom course before it drains. In so doing water inherently contacts and seeps through the blocks to the inside of the building. Thus, it was disclosed in U.S. Pat. No. 4,910,931 of Pardue to employ a system of upper water collection pans having downspouts leading from drain openings in the upper collection pans to drain collected water from the pans through the vertical block cavities in lower block courses to the next lower series of collection pans. A lowermost series of base collection pans then collected water drained through the vertical block cavities from the upper pans, and the water in the base collection pans were then diverted to the exterior of the wall using weeping spouts which projected laterally from the base collection pans. One of the difficulties of these kinds of drainage pan systems, however, is the necessity for the pans and masonry block cavities to be conformed to each other. In other words, the pans and other parts of the drainage system must be made to fit the particular masonry block shape and into the particular cavity dimensions. This often present considerable inconvenience to the masonry applicator who must be careful to obtain the correctly fitting drainage system devices to fit the masonry block structures.
In view of the disadvantages of the prior art, a novel and inventive masonry block drainage system is needed.
In surmounting the disadvantages of the prior art, the present invention provides a novel sheet-like masonry block drainage system which is convenient and easy to manufacture and use.
An exemplary masonry block drainage system of the present invention comprises a sheet-like waterproofing strip for water sealing a masonry block having at least one vertically-extending cavity therein; at least one drainage fabric member; and at least one weep member for draining water from the at least one drainage fabric member.
The waterproofing strip is preferably a rollable sheet, which can be made of polyolefin or other materials, having a width sufficient to prevent water from entering the vertically-extending cavities of masonry blocks. Exemplary waterproofing strips have means for providing a waterproofing seal around the masonry block cavities, such as a waterproofing adhesive or a keying structure for providing a bond with fresh mortar applied to the top of the masonry block. The drainage fabric member is preferably attached to the waterproofing strip by an adhesive or embedded into the strip, and permits seepage water to be drained by weep members which are preferably spaced at intervals along the side of the waterproofing strip. Water is drained from the drainage fabric member to a location external to the masonry block cavities.
The masonry block drainage device and systems herein described are preferably rollable so that they can be transported to and installed at the application site with relative ease. It is thus relatively easy to adjust the width of the waterproofing strip and drainage fabric member, such as by cutting, to facilitate installation at the site. More often than not, the masonry drainage systems can be produced in a number of standard widths and be applicable to variously shaped masonry blocks. The use of drainage fabric members which are generally coextensive with, and preferably adhered to, or otherwise attached to, the waterproofing strip member, allows seepage water to be collected and distributed to more than one weep member. This is indeed beneficial because it increases drainage rate and means that seepage water can be drained from mortar block cavities even when some weep members get clogged by dirt, debris, or masonry mortar.
Another benefit of the invention is that lateral migration of seepage water from one masonry block cavity to another can be achieved without the use of drilled or shaped holes in the block and without complex, expensive drainage pipes or structures placed within the masonry block cavities or under each masonry block course or the bottom-most course. Further features and advantages of the invention are provided hereinafter.